Method and apparatus for managing components in an it system

ABSTRACT

A system and method for collecting information on components in an information technology (IT) system. This embodiment features discovering components in the IT system, determining at least one dependency between two or more of the discovered components, and tracking changes to the discovered components and the dependency between two or more of the discovered components. The discovery of components can be carried out using fingerprints of components, which can include key elements of the component that exist in a full model of all of the elements of the component.

FIELD

The present invention relates generally to methods and systems formanaging the applications and components of an integrated informationtechnology or e-business computer system.

BACKGROUND OF THE INVENTION

Information technology (IT) and electronic business (e-business)solutions are important for business competitiveness and growth for manycompanies. An e-business or IT solution is typically a set ofapplications, or software packages, grouped together to solve a problem.A number of difficulties in IT systems and e-business solutions,however, can cause maintenance, planning, and management of thesesystems to be difficult. First, many IT systems are complex. Many ITsystems use a large number of applications that can exist on a largenumber of servers in a variety of locations. In addition, a large numberof participants can take part in an e-business solution. Many ITsystems, therefore, have a large number of components that form sizeablee-business systems of potentially overwhelming complexity.

Complexity for some IT systems results because it is often difficult todetermine what applications are running as part of the e-businesssolution, where those applications are running, and who is running thoseapplications. Relationships also exist between two or more applicationsin which one application uses another application in some way. Theserelationships, or “dependencies,” between applications are oftendifficult to determine. For example, common building blocks such asdatabases, web servers, and application servers can be used by manydifferent applications. Knowledge of dependencies in a system can beimportant. The failure of one application due to a bug or systemmalfunction can cause a larger breakdown of an e-business system due todependencies between the applications of the e-business system. Detailedknowledge of the organization of applications and the dependenciesbetween applications can provide valuable insight into repairing systemmalfunctions, planning for future growth, and managing the IT system.

The rapid change of many IT systems can also make management of ITsystems difficult. E-business solutions can change rapidly as technologychanges and as the needs of the e-business solution are modified. Newservers, databases, and applications can be added to upgrade a system orto improve performance. It can therefore become difficult and expensiveto track and fix problems, modify the e-business solution, and plan forfuture growth.

A lack of information about large, complex systems can also makemaintenance of IT systems difficult. The organization and informationabout a company's e-business system is typically locked up in the headsof one or more IT professionals within a company. The loss ofknowledgeable IT personnel can make system management time-consuming andburdensome for personnel who are not familiar with the entire structureof the IT system.

SUMMARY OF THE INVENTION

The invention features a method and apparatus for managing components inan IT system. Under one aspect of the invention, the method featuresdiscovering components in the IT system, determining at least onedependency between two or more of the discovered components, andtracking changes to the discovered components and the dependency betweentwo or more of the discovered components. The discovery of componentscan be carried out using fingerprints of components. These fingerprintscan include key elements of the component that exist in a full model ofall of the elements of the component. Refined components, which arecomponents that relate in some manner to another component (that is, therefined component is a specific version of the component or an optionalpiece that can be included with the component), can be discovered usingsubfingerprints that are activated upon the discovery of the component.A dependency is a relationship between two or more components in whichone component uses another component in some way, or in which onecomponent requires the existence of another component. After a componenthas been discovered, changes to the component can be tracked so that,for example, If personnel can more readily identify system changes thatmight hamper performance of the IT system.

Under another aspect of the invention, after components have beendiscovered, a visual map of the IT system can be generated. The visualmap can include depictions of the discovered components and thedependencies between the discovered components.

Under another aspect of the invention, an agent for collectinginformation on components in an IT system is provided. The agent can bea module that resides on a server in the IT system, and the agent canfeature an observer module to detect event information about theelements of the server and an analysis module to process the eventinformation. The analysis module can include (1) component discoveryrules to process event information and match event information withelements of one or more fingerprints of known components using anaccumulator, and (2) dependency discovery rules to discoverrelationships between components of the IT system.

Under another aspect of the invention, a network server can be usedalong with a plurality of agents, such as those described above. Eachagent can be installed on a separate server of the IT system, and eachagent can have the capability of discovering components that are localto the server on which the agent is installed. The agents can thentransmit information regarding events and discovered components to thenetwork server, where the information can be further processed todiscover components that span more than one server and to discoverdependencies between components that exist on separate servers.

Under yet another aspect of the invention, changes to components anddependencies in an IT system are tracked. In this embodiment, the methodfeatures generating a discovery message upon the discovery of anexisting component in the IT system, retrieving a list of elements ofthe existing component to track for changes, and transmitting a messageto an observer module to begin tracking changes for the elements in thelist.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a block diagram of a representative network in which thesystem can be implemented in one embodiment.

FIG. 2 is a block diagram of one embodiment of the architecture of anagent in the system of FIG. 1.

FIG. 3 is a block diagram of one embodiment of the architecture of thenetwork server in the system of FIG. 1.

FIG. 4 is a depiction of a fingerprint for a component that can be usedin one embodiment of the invention.

FIG. 5 a is a depiction of a subfingerprint for a component that can beused in conjunction with the fingerprint of FIG. 4.

FIG. 5 b is a depiction of a second subfingerprint for a component thatcan be used in conjunction with the fingerprint of FIG. 4.

FIG. 6 is a block diagram that illustrates the discovery of networkdependencies in one embodiment of the invention.

FIG. 7 a is a flow chart illustrating the processing of network messagesin one embodiment.

FIG. 7 b is a second flow chart illustrating the processing of networkmessages in one embodiment.

FIG. 7 c is a flow chart illustrating the processing of process-relatedmessages in one embodiment.

FIG. 7 d is a flow chart illustrating the processing of resourcemessages to determine dependencies in one embodiment.

FIG. 7 e is a flow chart illustrating the processing of resource removalmessages to remove dependencies in one embodiment.

FIG. 8 is a block diagram that illustrates the filtering of informationat different locations in the network of FIG. 1.

FIG. 9 is a flow chart illustrating the flow of event information duringoperation of the network of FIG. 1 in one embodiment of the invention.

FIG. 10 is a depiction of one embodiment of a visual map of one computerof a system that can be used in conjunction with the invention.

FIG. 11 is flow chart of the rules and processes in the operation of oneembodiment in response to an exist message in the network of FIG. 1.

FIG. 12 is flow chart of the rules and processes in the operation of oneembodiment in response to a delete message in the network of FIG. 1.

FIG. 13 is a flow chart of the rules and process in the operation of oneembodiment in response to a modify message in the network of FIG. 1.

FIG. 14 is flow chart of the rules and processes in the operation of oneembodiment in response to an application discovered message in thenetwork of FIG. 1.

DETAILED DESCRIPTION OF THE EMBODIMENTS OF THE INVENTION

The embodiments described herein provide methods and devices formanaging the hardware and software platforms and building blocks of anintegrated information technology (IT), e-business solution, or computersystem. Very briefly, a set of agents on servers of the system is usedto collect system event information by detecting low-level items in theIT system. Events are occurrences in the IT system, such as file orregistry creations, modifications, or deletions, or the discovery ofsuch components in the IT system. This event information is analyzedwithin the agents to filter out unneeded event information, such asminor file modifications that do not affect the system. The eventinformation is then analyzed in an agent or in a network server thatreceives information from all or a subset of the agents of the ITsystem. The components of the IT system are therefore discovered, andchanges to these components are tracked after discovery. In addition,dependencies, which are relationships between components, can bedetermined. A visual map of the IT system can then be created using theevent information, and this visual map can be updated as the IT systemchanges. The visual map can be used to locate and track system problems,help in developing system modifications, and aid in procuring thenecessary hardware for proper system performance.

As used throughout this specification, the term “component” refers toany item that can be detected, discovered, and/or tracked in an ITsystem. These items include the low-level items in an IT system such asfiles, directories, and registry settings, hardware of the system,database metadata, shared libraries, and Dynamic Link Libraries(“DLLs”), and also the higher-level components such as the applicationsof the IT system, along with other items. The term “application” will beused to refer to a component that is a piece of software for anidentifiable product. One application can therefore contain manycomponents. Examples of applications include an Apache web server, anOracle database, Microsoft® Word, and a collection of web pages andinstructions for managing a stock portfolio. An application can exist onone server or can be spread across multiple servers. One application caninclude a number of other applications. Microsoft® Office, for example,is an application that can include a number of other applications, suchas Word and Excel. Such an application can also be called a solution,which is a set of applications grouped together to provide a specificsolution to a specific problem.

Discovery of components can generally be either reactive or proactive.Reactive discovery is when an agent in the system is notified that anapplication or component has been installed, modified, or deleted, or isprovided with real-time messages regarding the creation of components topermit the agent to determine that an application or component has beeninstalled. In reactive discovery, the method and system react in realtime to event information in messages received from the observers andthe operating system as discussed below. This event information can beused to attempt to match fingerprints for discovery. In any case, asdiscussed in connection with the observers, the system and method canuse features of the server's operating system to detect events in realtime.

Proactive discovery, on the other hand, is used when an agent isinstalled on an existing system, when a system has restarted, or whenfurther information about the system is needed. In proactive discovery,the agent proactively scans or “crawls” the system to detect key files,registry entries, directory structures, and other information that willallow it to detect an installed component or application. Proactivediscovery can be used to step through the files on the system todetermine what is present. The detected files, registry entries, anddirectory structures can be used to match the fingerprints of the systemto discover components. In other embodiments, a map of the system can besaved so that the components of the system before a crash are known. If,after the fingerprints have been used to discover components on thesystem, the persist map is different from the actual components thathave been discovered, the system differs from before the crash or thehappening that caused the proactive scan.

A. System Architecture

FIG. 1 is a block diagram of a representative network in which theinvention can be implemented. The network includes a network server 10and a plurality of agents 12, 14, 16 that communicate either directly orindirectly with the network server 10. Generally, one or more agentsexist on each server 11, 13 for which management is desired and that isused by the IT system. It is also possible, however, for an agent toremotely monitor a server. FIG. 1, for instance, shows agent 12 remotelymonitoring sever 15. The IT system, as a whole, includes all of thecomputers, servers, and databases used by an e-business solution. Eachserver can be any computer or computer system, including a router, localdirector, or database system. The agents 12, 14, 16 collect and processsystem event information, which can then be communicated to the networkserver 10. Although FIG. 1 shows one network server 10, multiple networkservers 10 can exist. In the network of FIG. 1, a firewall 18 separatesagents 12, 14 from the network server 10. In one embodiment, a gatewayserver 20 exists in the same firewall segment as agents 12, 14 so thatthe agents 12, 14 can communicate with the gateway server 20, which isnearby. In other embodiments, a gateway server 20 is not used. Thegateway server 20, if used, sends the event information received fromagents 12, 14 to network server 10. In this manner, onlyserver-to-server communications need be firewall friendly.

The event information received by the network server 10 is stored innetwork database 22. This event information can then be accessed byusers through a user interface (UI) server 24 by using a browser 26,which can be any available browser, such as Netscape® Navigator orMicrosoft® Internet Explorer. It is also possible, in one embodiment, touse a browser 28 to access information through the firewall 18 to UIserver 24.

1. The Agents

The term “agent” will be used throughout this specification to refergenerally to a program module that resides on a server to be managed andthat collects and analyzes event information that describes occurrenceson the server of the IT system. The events monitored by an agent caninclude file creation, deletion, or modification, registry creation,deletion, or modification, network termination point creation, networkoutbound request creation, local directors, DNS information, SMTPinformation, database system information, security-related changes, andinformation regarding other components. A registry is a database used bythe Microsoft® Windows operating system (such as Windows 2000, XP, orNT) to store configuration information. Typically, at least one agentexists on each server or operating system of the IT system for whichmanagement is desired to monitor the server/system and collect relevantevent information. Each agent therefore can monitor the events of thespecific server or system on which it is installed. In otherembodiments, an agent can also monitor a server upon which the agentdoes not reside, as shown by agent 12 and server 15 in FIG. 1. As anexample, a database server need not have an agent installed on it inorder to monitor the database metadata, which can be monitored remotely.Although FIG. 1 depicts three agents 12, 14, 16, the number of agentsused within an embodiment will vary with the size and structure of theIT system.

In addition to collecting event information, the agents 12, 14, 16 candiscover components on the IT system that are local to the particularagent. If, for instance, Microsoft® Word exists on a server 11 runningagent 12, agent 12 can discover and track changes to the Microsoft® Wordapplication. Components that span more than one server, however, cannottypically be discovered or tracked using a single agent. For thisreason, event information is passed on to the network server 10, whereevent information from more than one agent can be processed. Web sitesthat retrieve information from multiple servers, for instance, areexamples of applications that span multiple servers and can bediscovered at the level of the network server 10. Because both theagents 12, 14, 16 and the network server 10 receive event information,discover components, and track changes, the architecture of agents 12,14, 16 and the network server 10 can, in one embodiment, be similar.

FIG. 2 is a block diagram that depicts the core services of one of theagents 12, 14, 16 of FIG. 1 in one embodiment. In general, the purposeof the agents 12, 14, 16 is to collect event information, performlow-level processing of the event information, and send the eventinformation to the network server 10 (through the gateway server 20 inan embodiment having a gateway server 20). In the embodiment of FIG. 2,the agent 12 includes an observer service 50, an analysis service 70,and a connection service 90. The connection service 90 handlescommunications between the agent 12 and the network server 10 (or thegateway server 20) and ensures that communications are secure. Theconnection service 90 receives event messages generated on the observerservice 50 through the analysis service 70 for communication to thenetwork server 10. In addition, the connection service 90 receivescommands from the network server 10 for communication to other servicesof the agent 12, as depicted in FIG. 2.

The observer service 50 is responsible for loading and configuring a setof observers that can be used to collect event information. An observeris a piece of code that determines if an event has occurred that issignificant to the IT system, generates a message describing the event,and passes the message to the agent 12 for further processing. Suchevents can be detected in real time as they occur or can be generated ina systematic “crawl” through a directory or server to collectinformation that already exists. Observers, therefore, “detect” thelow-level items in the IT system or subsystem. An observer can alsofilter event information to exclude certain events that are not ofparticular importance so that those events are not passed on to theanalysis service 70. The code of an observer interfaces with the hostoperating system, device drivers, databases, and other components of theserver 11 on which the agent 12 is installed to detect events. In oneembodiment, different observers can be used to detect differentcomponent classes of the server 11. For example, a first observer can beused to monitor the operating system, a second observer can be used tomonitor a first database, a third observer can be used to monitor asecond database, a fourth observer can be used to monitor a first devicedriver, and so forth.

As noted above, the observers generate messages having event informationthat describe an event upon the occurrence or detection of the event.FIG. 2 depicts the transmission of event information 94 in messagesbetween the observer service 50 and the analysis service 70. FIG. 2 alsodepicts the transmission of commands 92 from the analysis service 70 tothe observer service 50. These commands 92 are requests that aparticular function be performed or that more information be gatheredfor analysis. An example of such a command 92 is a request that adetailed description of a file, such as the file size and creation date,be retrieved and returned to the analysis service.

FIG. 2 depicts a number of observers running on agent 12. Theseobservers include process observer 52, network observer 54, databaseobserver 56, file driver 58 and file observer 62, and package observer60. The observers 52, 54, 56, 60, 62 depicted in the observer service 50of FIG. 2 are exemplary, and other observers can be used within thescope of the invention. In addition, multiple observers of the same typecan be used to monitor different events.

The file driver 58 and file observer 62 can be used to monitor filecreations, deletions, and modifications. In one embodiment, the fileobserver 62 and file driver 58 are implemented as described below.Numerous other implementations can also be used. A Solaris version ofthe file driver 58 can be implemented such that an interface is exposedto the file observer 62 through a pseudo device. Information regardingSolaris internals and pseudo devices is provided in Writing DeviceDrivers; Sun Microsystems, Inc.; February 2000; Part Number 805-7378-10;and Jim Mauro & Richard McDougall, “Solaris Internals,” Sun MicrosystemsPress (2001), ISBN 0-13-022496-0, p. 44-46, 513-564, 257-343. After loadand initialization, the file driver 58 hooks into the sysent table bysaving key system call function pointers and replacing them with theintercept code that allows the file driver 58 to intercept hooked calls.The calls of interest can include creat, creat64, open, open64, close,fork and exec, among others.

For this embodiment of file observer 62, Solaris calls the interceptcode that allows the driver 58 to intercept hooked calls when anapplication initiates a system call. At this point, if the interceptingfunction is enabled, it gathers data about the underlying storage device(i.e., physical, virtual, or network), full pathname of the file ordirectory, and supplied flags to the system call. To gather this data,the file driver 58 uses the virtual file system, vnode and processconstructs supplied by Solaris. Once gathered, the file driver 58compares this data with prerequisites, such as whether the WRITE flag isenabled or residing on a physical drive, to determine if the event isworth reporting. After the event passes these prerequisites, the filedriver 58 collects further information relevant to the event, such asfd, pid, ppid, uid and size, before passing it on to the file observer62 in the agent. After an event has been passed to the file observer 62,the file observer 62 translates the message to a common internal formatbefore determining if further processing is necessary or if the eventcan be sent straight to the analysis service 70.

The file observer 62 can generate a variety of messages regarding eventsin the system. These messages can, for example, include messagesindicating that a file exists, has been modified, or has been deleted.The file observer 62 can also respond to certain commands generated bythe analysis service 70. These commands to which the file observer 62responds can include commands to crawl through a specified directory tocollect event information, a command to retrieve details about a file, acommand to copy a file, and a command to filter certain information. Thefile observer 62 can also generate messages in response to the commandsindicated above, such as a message providing details about a file inresponse to a command message or a message indicating that a file hasbeen copied in response to a command message.

The process observer 52 generally collects information on processes inthe system that can be used to determine dependencies between certaincomponents. Such processes, for example, can include the use of a fileor application that already exists on the system. In one embodiment, aSolaris version of process observer 52 can be implemented such that aninterface is exposed to the process observer 52 through a pseudo device.After load and initialization, a driver hooks into the sysent table bysaving system call function pointers and replacing them with theintercept code that allows the driver to intercept hooked calls made byapplications. The calls of interest can include fork, exec, and exit,among others.

The processes of concern for this embodiment of process observer 52 aregenerally created by calling one of the members of the fork or execfamily of routines. Once an application initiates a system call, theintercept code that allows the driver to intercept hooked calls gathersinformation about the full pathname executable, fd, pid, ppid, uid andsupplied parameters. To gather this information, the driver usesinformation stored about the process through the virtual file system(vfs), vnode and process constructs supplied by Solaris. Due to thenature of certain system calls, such as the exit call, information canbe stored so that subsequent system calls can fill the message expectedby the analysis service 70. For instance, whenever an exec occurs, thefull pathname is saved using the pid as the key. This allows the processobserver 52 to send the full pathname when the exit occurs, whichnormally does not contain the full pathname. After information has beencollected by the process observer 52, it is sent to the analysis service70.

The process observer 52 can generate a variety of messages regardingevents in the system. These messages can, for example, include messagesindicating that a process exists or has been deleted. The processobserver 52 can also respond to certain commands generated by theanalysis service 70. Such commands can include, for example, a commandto retrieve details about a process. The process observer 52 can alsogenerate messages in response to commands, such as a message providingdetails about a process.

The network observer 54 generally gathers socket information andforwards this information for analysis. The network observer 54 can beused to detect outbound network connections and inbound networklisteners that can be used in the discovery process. In one embodiment,a Solaris version of network observer 54 can be implemented such that aninterface is exposed to the network observer 54 through a pseudo device.After load and initialization, a driver hooks into the sysent table bysaving system call function pointers and replacing them with theintercept code that allows the driver to intercept hooked calls made byapplications. The calls of interest can include socket, bind, listen,accept, connect and close, among others.

In this embodiment of the network observer 54, once an applicationinitiates a system call, the intercept code that allows the driver tointercept hooked calls determines the relevance of the event based oncharacteristics such as ip address, port number, and supplied flags. Ifthe event meets relevant requirements, the driver collects furtherinformation, such as fd, pid, ppid, uid, remote ip and port numberbefore passing it on to the network observer 54 in the agent. Thenetwork observer 54 can then determine if the event is relevant, and, ifso, pass it on to the analysis service 70.

The network observer 54 can generate a variety of messages regardingevents relating to network connections in the system. These messagescan, for example, include messages indicating that a network connectionexists or has been deleted. The network observer 54 can also respond tocertain commands generated by the analysis service 70. Such commands caninclude, for example, a command to retrieve details about a networkconnection. The network observer 54 can also generate messages inresponse to commands, such as a message providing details about anetwork connection.

The database observer 56 communicates with a relational or other type ofdatabase using an appropriate method, such as Oracle OCI libraries, MSSQL Server DB-LIB, or a vendor's Java Database Connectivity (JDBC)driver. The database observer 56 generally scans the metadata in thedatabase and reports this information through events to the analysisservice 70. The metadata can include the definition of tables, columns,constraints, triggers, stored procedures, permissions, ownership, andother information. This information can be used to track changes to thedatabase metadata, which allows an event message about thesemodifications to be generated. The database observer 56 can be usedprimarily for tracking changes to components in the IT system.

The database observer 56 can generate a variety of messages regardingevents relating to databases in the system. These messages can, forexample, include messages indicating that a database schema exists, hasbeen modified, or has been deleted. The database observer 56 can alsorespond to certain commands generated by the analysis service 70. Suchcommands can include, for example, a command to retrieve details about adatabase schema. The database observer 56 can also generate messages inresponse to commands, such as a message providing details about aschema.

The package observer 60 interfaces with operating system specificrepositories of known installed applications, which are sometimesreferred to as installed packages. For a Solaris embodiment, thisrepository is the package database as defined by the pkginfo command.Typically, these operating system repositories are incomplete in thatthey only contain a partial list of installed applications. For the setof applications that the operating system indicates as being installed,the package observer 60 can generate an event message to be sent to theanalysis service 70 regarding the applications. Such a message, forexample, can be a message indicating that an installation exists. Theanalysis service 70 can then verify whether the application existsthrough the discovery methods detailed throughout this specification.

A number of other observers that are not shown in FIG. 2 can also beused. Some of these observers include platform observers, domain nameservice (DNS) observers, load balancer observers, and registryobservers. A platform observer is an observer that collects informationregarding the server hardware and operating system. Generally, such anobserver generates an event message with information about the hardwareand operating system and sends it to the analysis service 70. The serverhardware information that is collected can include the total RAM memory,the architecture type (i.e., Intel x86, Sun Sparc, etc.), the number ofCPUs, the speed of CPUs, information regarding the hard disks (number,sizes, etc), information regarding local and remote mounted filesystems, and information regarding network adapters, such as IP and MACaddresses. The operating system information can include the vendor ofthe operating system, such as Microsoft® or Sun, the operating systemversion, the installation directory(ies), and the patch level.

A DNS observer retrieves the DNS names that correspond to the IPaddresses in use by an IT organization and reports this information tothe analysis service 70. The DNS observer communicates with a DNS serverusing appropriate industry standard protocols. This allows the networkserver 54 to organize the managed servers 11, 13, 15 by both the numericIP address, as reported by a platform observer, and the correspondingDNS names used when interacting with the managed servers 11, 13, 15.

A load balancer observer communicates with various Layer-4/load balancerswitches, such as a Cisco LocalDirector, to collect mapping information.The primary role of the load balancer observer is to retrieve theUniversal Resource Locators (URLs) to network IP address translationmappings, and report this information to the analysis service 70. Thisallows the network server 10 to organize the managed servers 11, 13, 15by both the numeric IP address as reported by the platform observer andthe corresponding URL's that are commonly used when interacting with themanaged servers 11, 13, 15.

A registry observer generates messages regarding changes to a Microsoft®Windows registry database. These messages can, for example, includemessages indicating that a registry key exists, has been modified, orhas been deleted. The registry observer can also respond to certaincommands generated by the analysis service 70. These commands to whichthe registry observer responds can include commands to crawl through theregistry keys beginning at a certain registry key to collect eventinformation, a command to retrieve details about a registry key, acommand to copy a registry key, and a command to filter certain registryinformation. The registry observer can also generate messages inresponse to the commands indicated above, such as a message providingdetails about a registry key in response to a command message or amessage indicating that a registry key has been copied in response to acommand message.

The analysis service 70 of the agent 12 of FIG. 2 processes the eventmessages generated by the observer service 50 to detect components,track changes to components, and discover dependencies betweencomponents on the local agent 12. Generally, a dependency is arelationship or association between two or more components in which onecomponent uses another component in some way, or in which one componentrequires the existence of another component, such as anotherapplication, database, or piece of hardware, in order for the componentto function properly. In the embodiment of FIG. 2, the analysis servicecontains filters 72, a rule engine 74, component detection rules 76,dependency detection rules 78, an accumulator 80 and persist map 82 (anystorage device), and a fingerprint database 84.

The analysis service 70 can, in one embodiment, use fingerprints toanalyze event information to determine if any of the components in thefingerprint database 84 exist on the server 11 of the agent 12. As willbe described in more detail below, the accumulator 80 can be used todetermine if all of the elements of a fingerprint exist, which indicatesthe presence of the component indicated by that fingerprint. The ruleengine 74, along with the component detection rules 76 and dependencydetection rules 78, contain the instructions used for the discovery andtracking procedures. The functions of the analysis service 70 will bedescribed in greater detail below.

2. The Network Server

FIG. 3 is a block diagram that depicts the core services of the networkserver 10 in one embodiment. The architecture of the network server 10can be similar to the architecture of the agent 12 described above inconnection with FIG. 2. The network server 10, for instance, contains aconnection service 140 and an analysis service 100. Each of theseservices provides substantially the same functionality as thecorresponding services within the agent 12. For instance, the connectionservice 140 handles communications, including event messages andcommands between the agents (or the gateway server 20) and the networkserver 10 and ensures that communications are secure. Unlike thearchitecture of the agents, the network server 10 does not typicallycontain an observer service. This is because the network server 10collects event information from a number of agents, which each containan observer service 50. The network server 10, however, does contain auser interface service 150 in one embodiment, as well as a modelingservice 120. The user interface service 150 allows a user to interactwith the system to monitor components and changes to the components thathave been tracked.

The modeling service 120 allows for the creation of models that can beused in discovery along with fingerprints, as will be described in moredetail below. The modeling service 120 contains a model creation service122, a fingerprint creation service 124, and a rule creation service 126that can create a database 130 of models, fingerprints, and rules.

The analysis service 100 of server 10 can be similar to the analysisservice 70 of the agent 12 of FIG. 2. The analysis service 100 containsfilters 102, a rule engine 104, component detection rules 106,dependency detection rules 108, and an accumulator 110 and persist map112. The analysis service 100 of the network server 10 can discovercomponents and dependencies that span more than one server. In addition,in some embodiments, the analysis service 100 of the network server 10can also discover components that exist solely on a single server.

B. Model-Based Discovery

The system and method described herein can discover components in the ITsystem, determine dependencies between the components, generate a visualmap of the components in the IT system, and then track changes to thediscovered components and the dependencies between the components. Thefirst step in one embodiment, therefore, is the discovery of componentsin the IT system, which determines what is installed and where it isinstalled.

Generally, a variety of discovery methods can be used within the scopeof the invention. One discovery method that can be used, and will bedescribed in greater detail below, is model-based discovery. As notedabove, the observers of the agents (FIG. 2) collect event information inthe IT system, and the event information is then analyzed by theanalysis service 70. A first level of analysis takes place within theanalysis service 70 of the agent 12, and a second level of analysistakes place within a similar analysis service 100 of the network server10 (FIG. 3), as will be described in greater detail below. In bothlevels of analysis, models can be used in discovery.

In a model-based discovery method, a model is constructed that defines acomponent, such as an application, and all of its component items, suchas files and registry keys. The model, therefore, is a collection ofdata that defines the presence and attributes of the elements of anapplication or component. Using the model, a matching set that describeskey elements of the application can be generated. This matching set,which can also be called a fingerprint, is a subset of the model for theapplication or component that uniquely identifies it, and the matchingset can contain information about the types of components, how thecomponents should relate (for example, directory structures), andattribute information about the components, such as the size of a file.A fingerprint can contain, for instance, the directory structure andfilenames of an application's files, the registry entries for theapplication (for Windows), and the contents of a few selected files orregistry keys.

As an example of model-based discovery, the agent 12 or network server10 can use a fingerprint to discover that an existing component has beeninstalled on the IT system through the use of the accumulation ofreal-time event information or by inspecting the actual contents of theIT system to see if components are present that match the fingerprint ofthe model of a known component. If components are present that match thefingerprint of the known component, the existing component on the ITsystem is discovered. The term “known component” will be used in thisspecification to refer to a component whose elements are known and cantherefore be modeled, whether that component exists on the IT system ornot. An “existing component,” on the other hand, will be used to referto an actual component that is installed on the IT system or is beinginstalled on the IT system.

As an example, a model for a component that is an application, such asMicrosoft® Word, can first be generated. Such a model will contain acollection of all of the data that define the presence, attributes, anddependencies of the components, such as the filenames and directorystructure of the files that make up Microsoft® Word. Because the modelfor Microsoft® Word will contain a large amount of data, a smallersubset of this data will be compiled into a fingerprint that can be usedfor discovery purposes. The fingerprint for Microsoft® Word, forinstance, could contain the key executable files and data that make upand uniquely define Microsoft® Word. During a discovery process,information about a number of events (that is, file or registry entrycreations or deletions) can be accumulated that form parts of thefingerprint for Microsoft® Word. When the last of these events isdiscovered, the fingerprint for Microsoft® Word has been matched and theexisting Microsoft® Word component on the IT system has been discovered.

1. Model Generation

In a model-based discovery method, a model of the component is firstgenerated so that a fingerprint can be created for use in discovery. Anumber of methods can be used to create models. FIG. 3 depicts amodeling service 120 in the network server 10 through which a user caninteract to create a model for a component. The modeling service 120contains a model creation service 122, a fingerprint creation service124, and a rule creation service 126 that can be used to define rulesfor use during discovery. In the network server 10 of FIG. 3,fingerprints can be contained in the database 130 of models,fingerprints, and rules. In the agent 12 of FIG. 2, similarly,fingerprints can be contained within the fingerprint database 84.

A model of a component can be generated using a variety of methods,including using manual inputs, tracked installs, kit scans, or autodiscovery. In each of these methods, the elements of a model for acomponent can be generated, and then these elements can be presented tothe user for verification. A graphical user interface, for instance, canbe used to present the elements to the user. The user can then check offelements that should not be used in the model so that the accuracy ofthe model can be controlled by the user.

A manual input method of model generation allows a person to select theitems that make up a component from a list of files, registry keys,dependencies, and other items. One such manual input method, forinstance, uses an installed instance of the application of the same typeas a source of the file lists and registry keys. A user can then selectall of the directories, files, and registry keys that make up anapplication in one manual input method of generating a model for acomponent.

A tracked install method of generating a model of a component, on theother hand, allows a person to denote the start and end of theinstallation of a component, such as an application. All of the files,registry keys, directory information, and other items that are created,modified, or deleted between the start time and end time of theinstallation can be considered parts of the application when buildingthe application model. This list of parts can then be modified by theuser to reduce the set of resources to be used by the application model.A user interface 150 (FIG. 3) can be provided to allow a user to denotethe start and stop time of the installation of an application.

A kit scan is another method that can be used to generate a model for acomponent. A kit scan allows a kitted form of the component, such as anInstallShield image, to be processed, and the internal list ofcomponents used to create the application can be modeled. In addition,the uninstall log of an already installed application can be scanned.This uninstall log lists the actions taken to actually perform theinstallation, which can be a good source of input for a model. In thismanner, a scan of the elements of the component are collected into amodel of the component. This type of model, therefore, can be generatedbefore the component is installed on the system. Kit scans can beperformed for a number of components that might later be used on asystem so that a model (and also a fingerprint) of the component willexist for the purpose of discovery.

Auto discovery is another method that can be used to generate a model tobe used for discovery. An auto discovery method uses clues provided bythe operating system to discover the elements of a component. Theseclues can include operating system pointers, process image file names,and framework knowledge. An operating system can contain pointers tofiles that make up an application. For example, Windows has registryentries that point to various pieces of an application, such asuninstall scripts. In addition, the operating system might contain alist of installed applications along with components of the applicationand dependencies. For example, the Windows Installer database, theSolaris packages database and the RedHat Linux RPM database can containa list of certain installed applications. A model of each installedapplication can therefore be readily constructed from operating systempointers. In another embodiment, operating system pointers can be usedto discover applications without first explicitly using the pointers tocreate models.

Process description clues used in auto discovery methods of modelgeneration include the observance of processes running on the operatingsystem that are loaded from files that can be tracked back to adirectory. An examination of the executable image that a process isrunning can be used to identify the directory from which the process waslaunched. This allows for the determination of which package launchedthe process. An application can therefore be modeled by the directoryand file structure that is present in the identified directories.

Framework knowledge clues used in auto discovery can be used to create amodel for some application frameworks that have a standardized way torepresent applications supported by the framework. For example, JSPimplementations install applications within a WEBAPPS directory andMicrosoft® ASP represents applications as directories that contain aglobal definition. An examination of the contents of these directoriescan therefore be used to create a model of the components.

2. Fingerprint Generation

After a model of a component has been created, a fingerprint, ormatching set, of the model can be constructed. This fingerprint, whichis a subset of the model for a known component, can be used to discoverthe presence of an existing component in the IT system. A model for acomponent, for instance, might contain hundreds of elements, but afingerprint for the same component might contain only ten to twentyelements. Although use a model of a known component may be ultra-precisein the discovery of an existing component because a full bill ofmaterials for the component will be matched, system constraints make theuse of fingerprints containing a subset of the elements of a modelbeneficial.

A fingerprint can be constructed from a model in a number of ways. Inone embodiment, all of the executable files of a model for a knowncomponent can be selected. In addition, the shared libraries and DLLs,which are libraries of executable functions or data that can be used byan application, can be selected, along with other elements thatnaturally define a component. Some percentage of these pieces can thenbe used in a fingerprint, and the pieces used should unambiguate thefingerprint so that it is unique for the component. In order tounambiguate the pieces for the fingerprint, the executable files can beassigned one weight, the shared libraries can be assigned anotherweight, and the DLLs can be assigned a third weight. In culling thepieces into a fingerprint, the weights can be used to ensure that keypieces of the component are included in the fingerprint. For example,the executable files can have the highest weights, which will ensurethat they will be included in the fingerprint. The DLLs could have thenext highest weights, which could ensure that a large number of DLLswill be included in the fingerprint.

As described above, a fingerprint contains a number of pieces that canbe matched in order to discover a component. The pieces that can bediscovered can be either passive elements or active elements. The term“passive element” will be used throughout this specification to refer tothe elements of a fingerprint that are matched or checked off for thediscovery of a component. These elements can also be referred to aslow-level elements. “Active elements,” on the other hand, are elementsof a fingerprint that trigger further searching, matching of elements,or matching of other subfingerprints in discovery.

The passive elements of a fingerprint for an application can, in oneembodiment, be a list of files that uniquely define the application.After all of these passive elements have been matched, one or moreactive elements can be used to further search for information that canidentify a version of an application or other optional components thatare commonly associated with an application. A “subfingerprint” is afingerprint that is used by the active elements of a parent fingerprintto discover a “refined component,” which can be either a specificversion of the component defined by the parent fingerprint or anoptional piece that might be contained under the application defined bythe parent fingerprint. Typically, a subfingerprint will containinformation that is more refined than the information contained in aparent fingerprint. For example, a parent fingerprint might contain alist of file names to search for, and the subfingerprint might containnot only file names, but the size of files as well. In addition, asubfingerprint can contain items that are not in the parent fingerprint.

In one embodiment, an active element might send a command to check thesize and checksum of one or more files, and the result of this checkcould lead to the discovery of a certain version of an application. Afingerprint could, for instance, be generic for all or more than oneversion of a component. FIG. 4 depicts one sample fingerprint F1 that isgeneric to different versions of a component. The fingerprint F1contains a number of passive elements, such as file1.exe, file2.txt,file3.dat, and organizational information, such as a directorystructure, that uniquely identify more than one version of theapplication. After all of the passive elements of the fingerprint F1have been matched, the active elements of fingerprint F1 might cause acommand message (FIGS. 2 and 3 illustrate commands 92 in transit), suchas a message to retrieve more detailed information, to be sent to anobserver to retrieve the size and checksum of file1.exe and then toattempt to match one or more subfingerprints. One or moresubfingerprints for fingerprint F1 can therefore exist, and thesesubfingerprints can be for different versions of the application. FIG. 5a depicts subfingerprint SUB1 and FIG. 5 b depicts subfingerprint SUB2.These subfingerprints SUB1 and SUB2 for the different versions of theapplication can include information about the size and checksum offile1.exe, and a certain version of the application can be discoveredupon the matching of this size/checksum information of subfingerprintSUB1 or subfingerprint SUB2.

In some embodiments, a single generic fingerprint may not be definableto uniquely identify all versions of an application. In such asituation, more than one parent fingerprint can be used to define theversions of the component. For instance, fingerprint F1 could be usedfor versions 1.0 to 1.9 of an application, and fingerprint F2 could beused for versions 2.0 to 2.9 of the application. Each fingerprint F1, F2could contain its own list of active and passive elements for discovery,and each fingerprint F1, F2 could rely on different subfingerprints forthe discovery of a specific version of the application.

In another embodiment, an active element of a fingerprint could send oneor more commands that cause an attempt to match other fingerprints foroptional pieces of a component. For instance, a fingerprint forMicrosoft® Office might have a number of passive elements that arematched to indicate the discovery of the Microsoft® Office component.After these passive elements have been matched, an active element maycause the attempt to match one or more subfingerprints of the Microsoft®Office fingerprint. These subfingerprints could be for applications thatcommonly exist within Microsoft® Office, such as Microsoft® Word, Excel,or Spell Checker. The subfingerprints for these applications becomeactive upon the generation of a message from an active element withinthe Microsoft® Office fingerprint, and this message causes the attemptto discover the components defined by these subfingerprints. In otherembodiments, the subfingerprints can remain active at all times. In suchembodiments, the elements of the fingerprint in addition to the elementsof the subfingerprint would have to be matched in order to discover therefined component of the subfingerprint.

In some embodiments of the invention, fingerprints and subfingerprintscan have multiple sets of elements used for different purposes. In oneof these embodiments, fingerprints and subfingerprints can have threesets of elements: a detect set, a complete set, and a minimum set. Whenall of the elements in the detect set have been matched, the componentof the fingerprint (or subfingerprint) can be considered to beinstalled. In this embodiment, the detect set can have only a portion ofthe elements necessary for a complete match of the component. In otherwords, when the elements of the detect set have been matched, thecomponent can be considered to be installed, but the level of certaintythat the component exists can be somewhat low. When the complete set ismatched, the component can be considered to be fully installed so thatit is known with certainty that the component has been installed. Theminimum set comes into play when a component is removed or deleted fromthe IT system. Generally, when all of the elements of the minimum sethave been removed and are no longer present in the IT system, thecomponent can be considered to be uninstalled. Because a full removal ofall of the elements of a component from the IT system does not alwaysoccur upon the removal or deletion of a component, the minimum set cancontain fewer elements than the detect or complete set in someembodiments.

C. Dependency Discovery

After components of the IT system have been discovered, discovery ofdependencies between different components of the system can be carriedout. Generally, as discussed above, a dependency is a relationship orassociation between two or more components in which one component usesanother component in some way, or in which one component requires theexistence of another component, such as another application, database,or piece of hardware, in order for the component to function properly.After two components are discovered in the IT system, certainrelationships (dependencies) between components can be discovered. Thesedependencies can be useful for an IT system administrator if one or morecomponents of a system crash or are not functioning properly. If therelationship of those components to other system components is known,resolving problems in the IT system can be accomplished more easily.

A number of types of dependencies can exist between components in asystem. One type of dependency is a shared library or object usagedependency. In such a dependency, the functionality of a firstapplication is dependent on a second application if the secondapplication exposes the first application through the use of a sharedlibrary, registry key, DLL, COM object, Java class, Inter-ProcessCommunication (IPC), shared memory segments, or other service. The firstapplication can, for instance, use the shared library, DLL, or otherelements of the second application. A variety of dependency discoverymethods can be used to discover these dependencies. Generally, eventinformation can be received that indicates directory structures andother activities that can be examined to determine dependencies. Forknown applications, it is possible to match a process running in thesystem with the libraries and class files that were used to start theprocess. This, in turn, allows an agent to associate an operating systemprocess with an application. In some instances, information regardingthe operating system processes, shared libraries, registry keys, andother program and class files are available from the operating system.If one component uses the libraries, registry keys, or files of anothercomponent, a relationship exists between the components and one of thecomponents is dependent upon the other component. In the agent 12 ofFIG. 2, the process observer 52 and accumulator 80 can be used todiscover these dependencies.

A second type of dependency is a network usage. In such a dependency, afirst application is dependent on a second application if the secondapplication uses resources that are exposed by a network connection,such as TCP/IP, by the first application. The second application's API,which is a set of routines, protocols, and tools used to build asoftware application, can, for instance, be called by the firstapplication during execution of the first application. In general, inorder to discovery network dependencies, outbound network connectionsare matched with network listeners so that the applications and serversin the dependency relationship can be determined. In the agent 12 ofFIG. 2, the network observer 54 and accumulator 80 can be used todiscover these dependencies.

A third type of dependency is a containment dependency. In a containmentdependency, a first application executes a second application, and thesecond application is therefore dependent on the first application. Insome configurations of containment dependencies, a first applicationcontains a second application in the directory structure of the firstapplication. In such a situation, the second application is dependent onthe first application. In another configuration, a first application haspointers to a second application that resides outside the directorystructure of the first application. In such a situation, the secondapplication is dependent on the first application. Another containmentdependency can be the existence of a component on a server In such asituation, the component depends on the server.

Discovery of containment dependencies can be accomplished using at leasttwo approaches. In the first approach, the outermost application can beprobed to determine the applications contained or used by that outermostapplication. For instance, code that interacts with the API of theoutermost application can be used to find the active applications withinthe outermost application, and hence to discover the dependencies.Another approach is to model the containment association so that thedependencies can be inferred. For example, for a first application, anyapplication stored in a particular directory of that first applicationcan be considered to be contained within the first application. Inaddition, the model for a first application can describe a component ofthe first application that contains information about other applicationsthat the first application will execute. This allows for the detectionof which other applications are executed by the first application.

FIG. 6 is a diagram of two machines, machines 1 and 2, which aredesignated by numerals 160 and 162, that can be used to illustratenetwork and containment dependencies. Machine 1 contains the TOMCATapplication. The TOMCAT application contains the WEBAPPS directory,which contains the EMPLOYEE PROFILES application. The EMPLOYEE PROFILESapplication is contained within TOMCAT, and a containment dependency ispresent.

Discovery of network usage dependencies can use processes running on theIT system that establish network listeners to accept incoming networkconnections. These processes can also create outbound networkconnections to remote systems. By tracking these listeners and outboundconnections, dependencies between systems and applications can bedetermined. Referring again to FIG. 6, a Microsoft® SQL server can beinstalled on machine 2 to listen for incoming connections on a certainport, port 1433, of the system. If a different application on machine 1creates an outbound connection to port 1433 of machine 2, an agent cancollect this information and can determine that a dependency existsbetween the two applications. The direction of the dependency isdictated by which application initiated the contact. In FIG. 6, theEMPLOYEE PROFILES application makes an outbound request 180 to port 1433of machine 2, and therefore EMPLOYEE PROFILES is dependent on Microsoft®SQL server on machine 2. In the agent 12 of FIG. 2, the network observer54 can be used to discover these dependencies. In one embodiment,inbound network requests can be ignored during discovery for efficiencypurposes, and instead outbound requests can be monitored.

In discovering network dependencies, it is possible to discover whichapplications on the servers are dependent upon each other in aprogressive manner. For instance, if an outbound network request isdetected, a dependency between two servers can be discovered If it isknown which applications are running on those servers, this informationcan be pieced together with the network connection information todetermine the dependencies between specific applications on the servers.

FIGS. 7 a-7 e are flow charts that illustrate embodiments that can beused to discover dependencies in an if system. FIG. 7 a illustrates theprocessing of messages generated by the network observer 54 (FIG. 2). Inparticular, FIG. 7 a at block 700 shows the processing of messagesgenerated upon the establishment of outbound network connections andinbound network listeners. A connection rule (block 702) is used toprocess these messages. Initially, at block 704, a determination is madeas the whether the outbound network connection or network listener is anunknown, or new, connection or listener. If the connection or listeneris unknown, then a message indicating a resource usage is generated(block 706). A resource usage indicates that some resource, such as anetwork connection endpoint, file, registry key, component, orapplication, is being used by one of the components in the IT system. Inthe context of network outbound connections or network listeners, such aresource usage message can indicate the server making the outboundconnection or network listener and the port used. As will be explainedbelow in connection with FIGS. 7 d and 7 e, these resource usagemessages can be used to discover components, such as softwareapplications, that use the same resources and therefore have adependency relationship.

If the network connection or listener is not new, then the connection orlistener existed in the past. A determination can then be made as towhether the application using the listener or connection has changed(block 708). If there has been no change, the resource usage messagepreviously generated for that network connection or listener need not bechanged, and the connection or listener message is dismissed (block712). If the application using the listener or connection has changed, amessage is generated to modify the resource usage message previouslygenerated for that resource usage to reflect the new application (block710).

FIG. 7 b shows the processing of a network listener or connectiondeleted message (block 720), which can be generated by the networkobserver 54 (FIG. 2). The connection rule processes the message, asindicated by block 722 of FIG. 7 b. Initially, at block 724, adetermination is made as to whether the connection or listener beingdeleted corresponds to a connection or listener that has previously beendetected. If the connection or listener has not previously beendetected, the connection or listener deleted message is dismissed (block728). If the connection or listener has previously been detected, aresource usage modify message is generated to indicate that the resourceis not currently being used by an application.

FIG. 7 c illustrates the processing of messages generated by the processobserver 52 (FIG. 2). In particular, FIG. 7 c shows the processing ofprocess exist and process detail messages (block 730) using a processrule (block 732). Initially, at block 734, a determination is made as towhether the process is an unknown or new process. If the process is notunknown (that is, if the process was known), a determination is made asto whether the list of open files used in running the process isdifferent than the previous list of open files (block 736). If thecurrent list of open files is different, for any files that are nolonger open, resource modify messages are generated to indicate thatthose files are no longer in use (block 738). In addition, for any newfiles that are open, resource add messages are generated to indicate theusage of those files (block 738). Such a resource usage message canindicate, for example, the name of the resource being used (such as afile name, registry key, or network port), the application that owns theresource, and the application that is using the resource.

If the process is unknown, a determination is made as to whether theowning component (or application) can be determined. If this applicationcannot be determined, the message is dismissed (block 744) because itwill not be useful in dependency discovery if the application using theresource is not known. If the component owning the process can bedetermined, a resource usage message is generated (block 742). The listof open files used by the process can be examined, and for each filethat is not owned by the application, a resource usage message can begenerated. Such a message can indicate, for example, the name of theresource being used (such as a file name), the application that owns theresource, and the application that is using the resource.

FIGS. 7 d and 7 e illustrate the processing of resource usage messagesin some embodiments. Generally, after the resource usage messages aregenerated as indicated above with respect to FIGS. 7 a-7 c, theaccumulator 80 (FIG. 2) is used to discover dependencies and thedirection of those dependencies.

Referring to FIG. 7 d, the processing of a resource usage message (block750) using a resource rule 752 is shown. FIG. 7 d shows the processingof resource usage messages relating to outbound network connections andnetwork listeners, as well as processes or files. Initially, at block754, the resource usage messages are added to the accumulator 80 (FIG.2). The accumulator 80 attempts to match outbound connections withlistener resources based on information about the resources used (block756 and 758). In some embodiments, the times of the usages can be usedin matching connections with listeners, although in other embodiments,specific time stamps are not used. The accumulator, for instance, cansearch for resource usage messages indicating that an outboundconnection and a listener use the same port of a server (that is, theoutbound connection points to a port that is the same port used by thelistener on a server). If a match is found, the direction of thedependency is determined at block 762. Generally, the application andserver that originated the outbound connection are dependent on theapplication and server having the port used the listener. In addition, adependency discovered message is generated at block 764. The resourceusage message can then be dismissed (block 766).

The accumulator 80 can also attempt to match resource usages for filesand processes on the same server (block 760). If the accumulator findsthat two applications use the same resource (such as a file), then adependency has been found. The direction of the dependency can then bedetermined (block 762) according to one of three different rules,although other rules could be used in other embodiments. For resourcesthat have no owning application (that is, no application was discoveredin which the resource is contained), each of the applications that isusing the resource is dependent upon the resource (this is a containmentdependency). For resources that have owning applications (that is, theresource is in the directory or model of an application), theapplication using the resource is dependent on the application that ownsthe resource unless the application using the resource is executing theapplication that owns the resource, in which case the relationship isreversed. Similar logic can be followed in determining thesedependencies if there are multiple levels of applications running otherapplications.

FIG. 7 e shows the processing of a resource usage removal message (block770) using a resource rule 772. FIG. 7 e shows the processing ofresource usage removal messages relating to outbound network connectionsand network listeners, as well as processes or files. Initially, atblock 774, the resource usage removal messages are added to theaccumulator 80 (FIG. 2). The accumulator 80 attempts to determine if adependency exists for the outbound connections that have been removed(block 778). If so, the dependency is marked as being suspect (block782). The accumulator 80 does nothing with messages regarding removednetwork listeners because a connection could still exist with thelistener being inactive. If the resource usage removal message relatesto a file, the accumulator 80 finds the dependencies associated withthat file and marks those dependencies as being suspect (blocks 780,782). Those dependencies marked as being suspect are then dealt with asdetailed below.

In some embodiments, messages indicating that dependencies are removedare not generated immediately upon the labeling of a dependency assuspect in block 782. Network connections are not typically maintainedconstantly, so dependencies spanning between servers are not indicatedby constant network connections and listeners. Similarly, files are notconstantly used by applications that might be dependent upon each other.For these reasons, messages indicating that dependencies are removed arenot always generated immediately upon a dependency being labeled assuspect. Instead, certain criteria can be examined to determine if thedependency should be removed (block 784). If, for instance, a certainlength of time (perhaps hours, days, or a week) passes with a dependencybeing labeled as suspect, a message indicating that the dependency isremoved could be generated. Such a message can be generated because thedependency relationship is not active. In another embodiment, othercriteria, such as absolute knowledge that the application has beenremoved, can be used to generate dependency removed messages. Theresource usage message can then be dismissed (block 786).

D. Tracking Changes and Filtering Events

After a component has been discovered and all of the pieces of thecomponent are known, it can be desirable to track any changes that aremade to the component, determine the differences in the contents ofthose modified components, and track changes to dependencies that existin the IT system. If a problem occurs in the functioning of the ITsystem, the tracked changes can be used to readily identify theapplication that has stopped working and the changes that may havecaused the application to stop working properly. Because a primaryhindrance to the successful upgrade and correction of IT systemmalfunctions is a lack of an accurate record of changes made to the ITsystem, a visual map of the IT system, including changes made tocomponents of the IT system over time, can be invaluable in remedyingsystem malfunctions.

In order to track these changes, any changes made to one or more of thefiles, directories, registry settings, or system configuration elementsin the fingerprints for the discovered components can be monitored. Insome embodiments, only key elements of the fingerprint for anapplication are monitored. In other embodiments, all of the elements inthe fingerprint are monitored. In still other embodiments, more thanwhat is in the fingerprint, such as all of the items in an application,can be monitored. For example, all of the items in a model for thecomponent can be tracked, and all of the items in the installationdirectory of an application can be tracked. In any event, this list ofelements to be tracked can be generated by compiling all of the elementsfor discovered components that are of interest. For example, theexecutable files for a discovered application can be tracked so thatmodifications can easily be discovered. In order to track contentchanges to components of the IT system, the analysis service of an agent12 or the network server 10 determines that an event message relates toan application that has already been discovered. The event message willthen be logged so that a record of the modification exists. After anevent message has been logged, it can be determined what content changewas made. For instance, if a file for a discovered application ismodified, the current version of the file can be compared to theprevious version of the file, and the differences between the content ofthe two versions can be determined. The modifications to the file cantherefore be tracked so that a user can easily see the changes made.

Another aspect of the invention involves the creation of a visual map ofthe files for each application, along with the structure of the entireIT system. The visual map can list the application, the files of theapplication, and an icon for the last change made to the file. Uponclicking this icon, the user can be presented with the text of the fileand the changes made to the file. The changes can be indicated byplacing deleted information in brackets and underlining added material,or by using any other comparing method. This illustration of the actualchanges to a file can be useful in troubleshooting for systemadministrators. In addition to information about changes that have beenmade to applications of the IT system, the visual map can allow a userto readily view the entire hardware platform of the IT system, as wellas the applications and infrastructure applications, such as webservers, databases, and other infrastructure applications installed on aparticular server. The visual map can also allow a user to select anapplication and view the list of files and registry entries associatedwith the application. The visual map can also be used to illustrate thedependencies between the various components of the IT system. The visualmap can be automatically updated as the IT system changes.

FIG. 8 shows the use of filtering to reduce the amount of eventinformation transmitted and processed in the system. Because a largenumber of events, such as file creations or deletions, can take placewithin a server in the IT system, filters can be used to reduce theamount of information transmitted using the system. Generally, eachfilter used in the IT system should let through the event informationthat matters for discovery and tracking, and filter out the remainingevent information. The event information that matters, generally, isevent information that corresponds to elements of a fingerprint or thatcorresponds to a detected or discovered component. In order to determinewhich event information to pass through a filter, therefore, thefingerprints used in the system can be analyzed.

Filters can be either exclusionary filters or inclusionary filters.Inclusionary filters let certain event messages that match a list ofelements in the filter pass through the filter and exclude or filter outall other event messages. The list of elements that matter for thefilter, and that will thus be passed through, are those elements thatcorrespond to elements in fingerprints. These will be the elements thatwill be matched during discovery and tracked after they are discovered.A list of all files in fingerprints of the system, along with all otherelements of the fingerprints, can therefore be created for use in thefilters of the system. Exclusionary filters, on the other hand, letthrough all event messages except certain messages that fit certaincriteria. For example, an exclusionary filter could filter out all eventinformation regarding the creation of any files with “.log” extensionsor any files that are larger than a certain size, and all other eventinformation could pass through the exclusionary filter.

In the embodiment of FIG. 8, event information can first be filtered inan observer 52, 54, 56, 60, 62 of the agent 12. After this eventinformation has been transmitted to the analysis service 70 of the agent12 and analyzed there, some of the event information can again befiltered out. If an application is purely local to an agent, forinstance, all event information that matches a fingerprint for thatapplication need not be passed through to the network server 10.Instead, the fingerprint for that application can be matched locally atthe agent 12 and then, after the application has been discovered, anapplication discovered message and other information about theapplication can be passed through to the network server 10. In thismanner, only a limited amount of event information will be passedthrough to the network server 10 from the agents of the system. A finalfiltering process can take place within the analysis service 100 of thenetwork server 10. This filtering process can filter out unneeded eventmessages so that every event that takes place within the IT system andis sent to the network server 10 is not saved within the network server10.

E. Operation of Component Discovery

FIG. 9 is a flow chart illustrating the operation of the network in oneembodiment. At block 200, fingerprints and subfingerprints are created.The modeling service 120 depicted in FIG. 3 can be used for the creationof these fingerprints and subfingerprints. Event information is thencollected by an observer, as depicted at block 202 of FIG. 9. Theobserver service 50 of the agents 12 of the system can be used to detectthese events (FIG. 2) as discussed above.

At block 204 of FIG. 9, the fingerprints and subfingerprints are used todiscover components in the IT system. Referring to FIG. 2, the analysisservice 70 of the agent 12, including the rule engine 74, accumulator80, and fingerprint database 84 can be used for the discovery ofcomponents at the agent-level. The analysis at the agent level generallyfocuses on the local system of the agent or the remote server that theagent monitors. As described above, event information of a fingerprintfrom the fingerprint database 84 can be matched in the accumulator 80until all of the passive elements of the fingerprint have been matched.At that point, an application discovered message can be generated by thefingerprint and the rule engine 74. In some embodiments, the activeelements of the fingerprint can then trigger command messages to searchfor certain types of elements, and subfingerprints can then be matchedto discover subcomponents that relate in some way to the component ofthe original fingerprint (that is, versions of the component or optionalpieces that can be used with the component). The subfingerprints canthen be matched in the same manner as the fingerprints.

The processing within the network server is similar to that within theagent. Referring to FIG. 3, the analysis service 100 of the networkserver 10, including the rule engine 104, accumulator 110, and database130 can be used for the discovery of components at the network-level,including components that span more than one server of the system.

It should be noted that an event message can be processed by more thanone processing service. Some types of event messages, for instance, canbe directed to component or subcomponent discovery through fingerprints.Other types of event messages, on the other hand, can be directed to adependency analysis service to discover dependencies between components.Block 206 of FIG. 9 depicts the act of discovering the dependenciesbetween components. Block 208 then depicts the tracking of changes todiscovered components in the IT system, as discussed in more detailabove.

A visual map can be generated to show the components of the system, aswell as the dependencies between components and the changes made tocomponents of the system. Block 210 of FIG. 9 depicts this act ofgenerating a visual map. This visual map can also show locations andassociations between components of the system. For example, serversexisting in one location or owned by particular entities can beindicated so that relations between hardware and software components ofthe system can be readily seen. FIG. 10 shows one possible embodiment ofa visual map of the components of one computer of a system. In FIG. 10,a summary section of the visual map contains information regarding thecomputer itself, such as the computer name 240. Another section of thisvisual map shows information regarding the storage devices 242 of thecomputer. A third and final section shows information regarding theinstalled applications 244, or discovered applications, of the computer.A first column in this section gives the name 250 of the application, asecond column gives the version 252 of the application that wasdiscovered, a third column gives the date of the last change 254 to theapplication, and a fourth column gives the installation date 256 of theapplication. In one embodiment, a user can click on a date in the lastchange column 254 to be given details of the recent changes to theapplication.

F. Examples of Operation

FIGS. 11-14 depict flow charts of the operation of the method and systemin an agent in response to four different types of messages that can becreated in the network: exist messages; delete messages; modifiedmessages; and application discovered messages. FIGS. 11-14 depict onlyfour varieties of event messages. In addition to these type of messages,other event messages, such as those discussed above in relation to theobservers, can be processed. Event messages regarding outbound networkrequests, for instance, can be analyzed for dependency relationships.

1. Exist Messages

FIG. 11 shows the functions in one embodiment after a message indicatingthat a file, registry, or database schema exists or has been created isgenerated by an observer. FIG. 11 lists exist messages relating tofiles, registries, and schemas (see block 300). For simplicity, however,the following discussion relating to exist messages refers specificallyto files, although it should be noted that the same procedures can befollowed for registries and schemas. In addition, the functions depictedin FIG. 11 can be carried out in the either in the agent or in thenetwork server 10 of the system.

Initially, as indicated by block 300 of FIG. 11, a message indicatingthat a file has been created is received. Such a message can begenerated, in one embodiment, by the file observer 62 of the agent 12(FIG. 2) whenever a new file is detected. The detection of a new filecan occur through reactive notification by a driver that detects thefile being created in real-time or through proactive notification bycrawling of the file system of the server on which an agent resides.

In the embodiment of FIG. 11, each file create message is a candidatefor three possible system rules: a component (or package) detect rule302, a track changes rule 315, and a track install rule 324. Each filecreate message can be subject to one or more of these rules, andgenerally a filter can be used for the logic set for each rule todetermine if the functions associated with the rule will be performed.For example, a filter can determine if a created file is of the type offile that might matter for component detection and, if so, the messagefor the created file will be passed on to the logic of the componentdetect rule 302. If the event message fails the filter, the eventmessage is discarded.

The component detect rule. 302 is generally responsible for adding theinformation received in the file create message to an accumulator thatcan be used for discovery, as indicated by block 304 of FIG. 11. In anembodiment in which the component is an application, for instance, anumber of files and registry keys could make up the passive elements ofa fingerprint for a known component. Referring to FIG. 2, the componentdetection rules 76 along with the accumulator 80 and fingerprintdatabase 84 will be used to determine if the passive portions of anyfingerprints have now been fully matched (block 306 of FIG. 11 depictsthis determination). If all of the passive elements of a fingerprinthave been matched, a component detected message will be generated, asindicated by block 308. Such a message will then be used in theapplication discovered embodiment illustrated in FIG. 14.

Referring again to FIG. 11, if all of the passive elements of afingerprint do match, a determination will be made as to whether anyactive elements exist for the fingerprint, as indicated by block 310. Ifa fingerprint does contain active elements, the active elementssubfingerprints will be activated and these subfingerprints will beadded to the set of fingerprints being considered by the accumulator. Asdiscussed above in connection with model-based discovery,subfingerprints can be used to discover, in some embodiments, versionsof an application or optional pieces that can be used with a component.Each of these active element subfingerprints can have one or more activeelements associated with them that can be executed, as indicated byblock 312. These actions can, for instance, allow the agents to gatheradditional information that can be used in the discovery process tomatch the subfingerprints for subcomponents that might exist in the ITsystem. These actions can include, for instance, commands to gather moredetailed information about files, such as the size of certain files, orabout registry keys or directory structures. Referring again to FIG. 2,the commands 92 to gather more detailed information can be sent to theobserver service 50 of the agent 12 for use in discovery. Further eventmessages 94 (FIG. 2) received during this active discovery process canthen be used to determine if a subfingerprint has been matched, thusindicating the presence of a subcomponent on the IT system. After theseprocesses of the component detect rule 302 (FIG. 11) have beencompleted, the file create message can be logged and the event messagecan be dismissed as having been processed, as indicated by block 314.

The track changes rule 315 is the second possible rule set that can becarried out for a file create message. Generally, a file exists messagewill be subject to the track changes rule 315 if the created file passesthrough a filter set that the file is of the type for which changes arebeing tracked. Generally, file changes are tracked for files that arepart of applications that have been discovered in the system already(that is, installed components). A determination is therefore made as towhether the file has been created and is part of an installed componentor application for which tracking changes would be appropriate. Block316 of FIG. 11 depicts this determination. If the file is not part of aninstalled component, the message is dismissed, as indicated by block322.

If the file is part of an installed component, the event message isforwarded to the network server (block 317). The event message caninclude information such as the user name of the person who created thefile and when it was created. If the file is one of the items for whichchanges are being tracked (block 318), the agent generates a command tocopy the contents of the file at block 319. This command is forwarded tothe appropriate observer (block 320) so that the contents of the filecan be copied. A copy of the file contents is then made so that thesecontents can later be used in tracking changes to the file contents ifthe file is modified.

The track install rule 324 is the third possible rule set than can beperformed for a file create message 300. Initially, this rule determinesif a track install is in progress, as indicated by block 326 of FIG. 11.In one embodiment, a track install can be indicated by a user of thesystem who is installing an application. If such a track install is inprogress, a determination can be made as to which installation andapplication the created message should be attributed. Block 328 depictsthe determination of the initiating process identifier (“PID”). Block330 depicts the selection of target track details lists. Block 332indicates the addition of the file create message to the list ofselected details of the application being installed. After theprocessing of the track install rules, or if a track install is not inprogress, the file create message can be dismissed, as indicated byblock 334.

2. Delete Messages

FIG. 12 shows the functions in one embodiment after a message indicatingthat a file, registry setting, or schema has been deleted is generatedby the system. It should be noted that the functions depicted in FIG. 12can be carried out in either an agent or in the network server 12 of thesystem. The discussion below for FIG. 12 will focus on registrysettings, but it should be noted that the same procedures can befollowed for deleted files and schemas as well.

Initially, as indicated by block 400 of FIG. 12, a message indicatingthat a registry setting has been deleted is received. A registry deletedmessage can be generated by the registry observer of the agent 12 (FIG.2) whenever a registry deletion is detected, and reactive notificationor proactive notification can be used.

In the embodiment of FIG. 12, each registry setting deleted message is acandidate for three possible system rules: a component detect rule 402,a track changes rule 417, and a track install rule 426. Fewer or morerules could be used in other embodiments. The component detect rule 402is generally responsible for removing the information received in theregistry setting deleted message from an accumulator that can be usedfor discovery, as indicated by block 404 of FIG. 12. A determination ismade as to whether any fingerprints have lost elements. FIG. 12 depictsthe determination of whether any elements from a complete set of afingerprint have been lost, as indicated by block 406. If one or morefingerprints have lost an element from the complete set, a componentdamaged message can be generated, as indicated by block 408. Such acomponent damaged message can indicate to users of the IT system thatsomething has changed for components that had previously beendiscovered.

If a component had previously been discovered and later loses anelement, a “weak” match for the corresponding fingerprint can exist.Such a weak match indicates that, at some point, all of the elements ofthe fingerprint were matched, but one or more files changed so that thefingerprint is no longer entirely matched. This weak match can indicate,in some embodiments, that the component still exists, but may need to bereconstructed to be useful. In other words, if the component is anapplication, the application has been damaged, but it is believed thatthe application still exists.

If the minimum set a fingerprint becomes empty such that no elements inthe minimum set of the fingerprint remain matched (block 410), acomponent uninstalled message can be generated, as indicated by block412. If none of the elements of the minimum set of the fingerprint arematched any longer, it can be assumed that the component has beenuninstalled, deleted, or is thoroughly damaged. If the minimum set of afingerprint becomes empty, any active element subfingerprints can bedeactivated so that discovery of the corresponding subcomponents will nolonger be attempted (block 414 of FIG. 12). The deactivation of theactive element subfingerprints also decreases the amount of informationsought to be discovered by the agents of the IT system. The activeelement subfingerprints can be deactivated and removed from the set offingerprints being considered by the accumulator. After the deactivationof active elements for any fingerprint that is empty, the registrysetting deleted message can be dismissed (block 416) as having beenfully processed. In other embodiments, all of the subfingerprints remainactive at all times.

The track changes rule 417 is the second possible rule set that can becarried out for a registry setting deleted message. Block 418 of FIG. 12depicts an act of determining if the registry setting is part of aninstalled component. If not, the message is discarded, as indicated atblock 422. If the registry setting is part of an installed application,the message is forwarded to the network server so that the deletion canbe noted. If the registry setting is a registry setting for whichcontent changes are being tracked, as determined at block 420, thecontents of the registry setting that were saved when the registrysetting was created or modified are deleted so that unneeded informationis not retained on the system (block 421).

The track install rule 426 is the third possible rule set than can beperformed for a registry setting deleted message. Initially, this ruledetermines if a track install is in progress, as indicated by block 428of FIG. 12. In one embodiment, a track install can be indicated by auser of the system who is installing an application. If such a trackinstall is in progress, a determination can be made as to whichinstallation and application the message should be attributed. Block 430depicts the determination of the initiating process identifier. Block432 depicts the selection of target track details list. Block 434indicates the addition of the file delete message to the list ofselected details of the application being installed. After theprocessing of the track install rules, the registry setting deletedmessage can be dismissed, as indicated by block 436.

3. Modify Messages

FIG. 13 shows the functions in one embodiment after a message indicatingthat a file, registry, or schema has been modified is generated by anobserver. FIG. 13 lists modify messages relating to files, registries,and schemas (see block 450). For simplicity, however, the followingdiscussion relating to modify messages refers specifically to files,although it should be noted that the same procedures can be followed forregistries and schemas. In addition, the functions depicted in FIG. 13can be carried out in the either in the agent or in the network server10 of the system.

Initially, as indicated by block 450 of FIG. 13, a message indicatingthat a file has been modified is received. The detection of a modifiedfile can occur through reactive notification by a driver that detectsthe file being modified in real-time or through proactive notificationby crawling of the file system of the server on which an agent resides.

In the embodiment of FIG. 13, each file modified message is a candidatefor three possible system rules: a component (or package) detect rule452, a track changes rule 466, and a track install rule 478. Each filemodified message can be subject to one or more of these rules, andgenerally a filter can be used for the logic set for each rule todetermine if the functions associated with the rule will be performed.

The component detect rule 452 works generally the same as the componentdetect rule 302 for an exist message in FIG. 11, and the componentdetect rule 452 is generally responsible for adding the informationreceived in the file modify message to an accumulator that can be usedfor discovery, as indicated by block 454 of FIG. 13. In an embodiment inwhich the component is an application, for instance, a number of filesand registry keys could make up the passive elements of a fingerprintfor a known component. Referring to FIG. 2, the component detectionrules 76 along with the accumulator 80 and fingerprint database 84 willbe used to determine if the passive portions of any fingerprints havenow been fully matched (block 456 of FIG. 13 depicts thisdetermination). If all of the passive elements of a fingerprint havebeen matched, a component discovered message will be generated, asindicated by block 458. Such a message will then be used in theapplication discovered embodiment illustrated in FIG. 14.

Referring again to FIG. 13, if all of the passive elements of afingerprint do match, a determination will be made as to whether anyactive elements exist for the fingerprint, as indicated by block 460. Ifa fingerprint does contain active elements, the active elementssubfingerprints will be activated and these subfingerprints will beadded to the set of fingerprints being considered by the accumulator.Generally, the active elements of the fingerprint can then be executed,as block 462 indicates. Such features work substantially the same asdiscussed in connection with blocks 310 and 312 of FIG. 11. After theseprocesses of the component detect rule 452 (FIG. 13) have beencompleted, the file modified message can be logged and the event messagecan be dismissed as having been processed, as indicated by block 464.

The track changes rule 466 is the second possible rule set that can becarried out for a file modified message. Generally, file modificationsare tracked for files that are part of applications that have beendiscovered in the system already (that is, installed components). Adetermination is therefore made as to whether the file is part of aninstalled component or application for which tracking changes would beappropriate. Block 468 of FIG. 13 depicts this determination. If thefile is not part of an installed component, the message is dismissed, asindicated by block 477.

If the file is part of an installed component, the event message isforwarded to the network server for analysis (block 470). If the file isone of the items for which content changes are being tracked (block472), a copy command is generated (block 473) and forwarded to theobserver. The observer then copies the contents of the file and forwardsthese contents to the analysis engine of the agent (block 474). Theanalysis engine of the agent will then have the current contents of thefile and the previous contents of the file (that is, the contents beforethe modification). The analysis engine can therefore compare the currentcontents to the previous contents and determine the differences incontent (block 475). A message containing the differences in content canthen be forwarded to the network server (block 476). In addition, theanalysis engine can save the current contents of the file so that theycan be used to determine differences if the file is modified again. Theevent message can then be discarded, as indicated by block 477.

The track install rule 478 is the third possible rule set that can beperformed for a file modified message 450. Initially, this ruledetermines if a track install is in progress, as indicated by block 480of FIG. 13. In one embodiment, a track install can be indicated by auser of the system who is installing an application. If such a trackinstall is in progress, a determination can be made as to whichinstallation and application the created message should be attributed.Block 482 depicts the determination of the process identifier (“PID”).Block 484 depicts the selection of target track details lists. Block 486indicates the addition of the file modified message to the list ofselected details of the application being installed. After theprocessing of the track install rules, or if a track install is not inprogress, the file modified message can be dismissed, as indicated byblock 334.

4. Application Discovered Messages

FIG. 14 shows the functions in one embodiment after a message indicatingthat an application has been discovered has been generated by thesystem. As noted earlier, an accumulator within an agent or networkserver generates an application discovered message when a fingerprinthas been matched (or when the complete or detect set of a fingerprinthas been matched). Initially, as indicated by block 500 of FIG. 14, amessage indicating that an application has been discovered is received.

In the embodiment of FIG. 14, each application discovered message is acandidate for three possible system rules: a component detect rule 502,a track changes rule 508, and a track install rule 520. Fewer or morerules can be used in other embodiments. In some embodiments, filters arenot used for application discovered messages or other messages generatedby the agents or network server. Generally, these filters are not usedin this embodiment because every discovered application can beconsidered important for some aspects of the IT system.

The component detect rule 502 is generally responsible for the limitedtask of forwarding a message to the network server 10 indicating that anapplication has been installed, as indicated by block 504 of FIG. 14.Block 506 then depicts the dismissal of the application discoveredmessage. Generally, the file create rules of FIG. 11 and the file deleterules of FIG. 12 can be processed within the agents of the system, and,as indicated in block 504 of FIG. 14, application discovered messagescan be delivered to the network server 10 for further processing.

The track changes rule 508 is the second possible rule set that can becarried out for an application discovered message. Generally, this ruleis responsible for determining if the application that has just beendiscovered has content change tracking enabled and, if so, it determinesany processing that needs to be done to set up such tracking. Initially,therefore, a track changes list and filters for the application can beretrieved, as indicated by block 510 of FIG. 14. If this list of files,registry keys, and other elements to be tracked and the list of filtersis empty, the application discovered message can be dismissed by thisrule, as indicated by block 518. If the determination of whether thereare files and filters for which changes will be tracked (block 512)shows that such files and filters exist, a copy message will begenerated to get the initial version of items to track for theapplication, as indicated by block 514. Block 516 then shows thedelivery of a message to an observer (FIG. 2) of the agents so that thetracking of changes can take place within the agents of the system.

The track install rule 520 is the third possible rule set than can beperformed for an application discovered message. This rule isresponsible for matching up the set of tracked installation details withany applications that are discovered. This procedure can be complicatedbecause a number of track installs can be present at any given time. Ifsuch a track install is in progress (determined at block 522 of FIG.14), a determination can be made as to which installation andapplication the created message should be attributed. If a track installis in progress, block 524 depicts the retrieval of a list of trackedinstalls that are in progress. An attempt is then made to match the newapplication with the correct set of installation details, which can beindicated by a PID (block 525). If the details of the track install areavailable, as determined at block 526, an application install detailsmessage can be generated (block 528). The installation details can thenbe forwarded to the network server 10. After the processing of the trackinstall rules, the application discovered message can be dismissed, asindicated by block 532.

The agents can also perform actions in response to other event messagesreceived in the system. For instance, event messages can be generatedthat indicate that a copy procedure, such as the copy of a file,registry key, or schema, has been completed. In response to such amessage, the track changes rule can determine if the previous version ofthe file, registry key, or schema is available. If the previous versionis available, the new copy of the file, registry key, or schema iscompared to the old copy, and the differences are determined. A messagecontaining the differences between the copies can then be generated andforwarded to the server. Difference messages can then be readily usedfor tracking changes in the IT system.

The accompanying Figures depict embodiments of the methods and devicesof the present invention, and features and components thereof. While thepresent invention has been described with reference to severalembodiments thereof, those skilled in the art will recognize variouschanges that may be made without departing from the spirit and scope ofthe claimed invention. Accordingly, the invention is not limited to whatis shown in the drawings and described in the specification, but only asindicated in the appended claims.

1-44. (canceled)
 45. A computer-readable medium storing programinstructions executable to: store a fingerprint specifying a pluralityof attributes of a component of an information technology (IT) system;automatically discover the existence of the component in the IT systemusing the fingerprint, wherein automatically discovering the existenceof the component comprises: receiving a plurality of event messagesindicating a plurality of real-time events that occur in the IT system,wherein each event message matches a respective attribute specified bythe fingerprint; and determining that event messages matching eachattribute of the plurality of attributes specified by the fingerprinthave been received.
 46. The computer-readable medium of claim 45,wherein the component is a software application.
 47. Thecomputer-readable medium of claim 45, wherein the plurality of eventmessages includes a first event message indicating a first real-timeevent selected from the following real-time events: a file creation, afile deletion, and a file modification.
 48. The computer-readable mediumof claim 45, wherein the plurality of event messages includes a firstevent message indicating a first real-time event selected from thefollowing real-time events: a registry key creation, a registry keydeletion, and a registry key modification.
 49. The computer-readablemedium of claim 45, wherein the plurality of event messages includes afirst event message indicating detection of a particular element of thecomponent in the IT system.
 50. The computer-readable medium of claim45, wherein the program instructions are further executable to: afterdiscovering the existence of the component, receive a subsequent eventmessage indicating that an element of the component was deleted; andindicate that the component has been damaged in response to thesubsequent event message.
 51. The computer-readable medium of claim 45,wherein the program instructions are further executable to: afterdiscovering the existence of the component, receive one or moresubsequent event messages indicating that one or more elements of thecomponent were deleted; and indicate that the component has beenuninstalled from the IT system in response to the one or more subsequentevent messages.
 52. The computer-readable medium of claim 45, whereinthe program instructions are further executable to track changes to thecomponent after discovering the component.
 53. The computer-readablemedium of claim 45, wherein the program instructions are furtherexecutable to: store a subfingerprint specifying one or more attributesof a refinement of the component; in response to discovering thecomponent, perform one or more commands to obtain information regardingthe component; and automatically discover the refinement of thecomponent in the IT system by matching the information regarding thecomponent to the one or more attributes of the refinement of thecomponent specified by the subfingerprint.
 54. The computer-readablemedium of claim 53, wherein the refinement of the component is aparticular version of the component, wherein discovering the refinementof the component comprises discovering that the particular version ofthe component exists in the IT system.
 55. The computer-readable mediumof claim 53, wherein the refinement of the component is an optionalpiece of the component, wherein discovering the refinement of thecomponent comprises discovering that the optional piece of the componentexists in the IT system.
 56. A system comprising: one or moreprocessors; and memory storing program instructions; wherein the programinstructions are executable by the one or more processors to: store afingerprint specifying a plurality of attributes of a component of aninformation technology (IT) system; automatically discover the existenceof the component in the IT system using the fingerprint, whereinautomatically discovering the existence of the component comprises:receiving a plurality of event messages indicating a plurality ofreal-time events that occur in the IT system, wherein each event messagematches a respective attribute specified by the fingerprint; anddetermining that event messages matching each attribute of the pluralityof attributes specified by the fingerprint have been received.
 57. Thesystem of claim 56, wherein the component is a software application. 58.The system of claim 56, wherein the plurality of event messages includesa first event message indicating a first real-time event selected fromthe following real-time events: a file creation, a file deletion, and afile modification.
 59. The system of claim 56, wherein the plurality ofevent messages includes a first event message indicating a firstreal-time event selected from the following real-time events: a registrykey creation, a registry key deletion, and a registry key modification.60. The system of claim 56, wherein the program instructions are furtherexecutable by the one or more processors to track changes to thecomponent after discovering the component.
 61. The system of claim 56,wherein the program instructions are further executable by the one ormore processors to: store a subfingerprint specifying one or moreattributes of a refinement of the component; in response to discoveringthe component, perform one or more commands to obtain informationregarding the component; and automatically discover the refinement ofthe component in the IT system by matching the information regarding thecomponent to the one or more attributes of the refinement of thecomponent specified by the subfingerprint.
 62. The system of claim 61,wherein the refinement of the component is a particular version of thecomponent, wherein discovering the refinement of the component comprisesdiscovering that the particular version of the component exists in theIT system.
 63. The system of claim 61, wherein the refinement of thecomponent is an optional piece of the component, wherein discovering therefinement of the component comprises discovering that the optionalpiece of the component exists in the IT system.
 64. Acomputer-implemented method comprising: storing a fingerprint specifyinga plurality of attributes of a component of an information technology(IT) system; automatically discovering the existence of the component inthe IT system using the fingerprint, wherein automatically discoveringthe existence of the component comprises: receiving a plurality of eventmessages indicating a plurality of real-time events that occur in the ITsystem, wherein each event message matches a respective attributespecified by the fingerprint; and determining that event messagesmatching each attribute of the plurality of attributes specified by thefingerprint have been received.